In typical cold gas dynamic spraying, particles for the coating are accelerated to supersonic speed by means of a convergent-divergent nozzle so that they, on account of their impressed kinetic energy, remain adhered to the surface which is to be coated. In this case, the kinetic energy of the particles leads to a plastic deformation, wherein the coating particles upon impact are fused only on their surface. In comparison to other thermal spraying methods, it is referred to as cold gas dynamic spraying because it is carried out at comparatively low temperatures at which the coating particles in the main remain solid. Cold gas dynamic spraying, also referred to as kinetic spraying, includes a cold gas spraying plant with a gas heating device for heating a gas. Connected to the gas heating device is a stagnation chamber which on the outlet side is connected to a convergent-divergent nozzle, e.g., a Laval nozzle. Convergent-divergent nozzles have a converging section and also a diverging section which are connected by means of a nozzle neck. The convergent-divergent nozzle creates on the outlet side a powder jet in the form of a gas flow, with particles located therein, at high speed, preferably at supersonic speed.
According to DE 10 2004 058 806 A1, for example, at least one structured, electrically insulating layer and a structured, electrically conducting layer can be formed on a cooling body. In this method, masks include openings which correspond to the structuring. The structured layers serve as circuit structures which satisfy electrical requirements such as a specified conductor cross section. The layers can lie one on top of the other in a plurality of layer planes.
D.-Y. Kim et al., “Cold Spray Deposition of Copper Electrodes on Silicon and Glass Substrates”, Journal of Thermal Spray Technology, Vol. 22, October 2013, teaches that the production of printed conductors by means of cold gas dynamic spraying with the aid of masks that lie upon the substrate nevertheless poses the problem that the masks which are required for this have openings of small width. The ratio between the width of the mask openings and the mask thickness leads in this case to flow conditions of the cold gas jet in the mask opening which makes deposition of the particles difficult. Specifically, a back flow may lead to a triangular cross section of the deposited material forming on the mask walls, wherein the point of this cross section lies in the middle of the mask opening and faces the cold gas jet. No material remains adhered to the walls to the mask opening itself. It is essential for the production of printed conductors that the cross section of the printed conductor is suitable for the transmission of the required electric current—the generated cross-sectional shape being of minor importance in comparison to this.
To avoid the flow conditions which are unfavorable for the deposition of rectangular cross sections, according to K.-R. Ernst et al., “Application Diversity of Cold Gas Spraying”, Conference Proceedings of the Thermal Spraying Community e.V., Press: Gerdfried Wolferstetter, Gilching 2012, it is proposed that the mask does not have to be laid upon the carrier component for cold gas spraying but this can be fixed at a certain distance from the carrier component. This measure, however, has the effect that with increasing mask distance from the carrier component the flanks of the sprayed surfaces extend beyond the dimensions of the mask opening. The cross section of the structures which are produced in the mask openings is therefore not rectangular either but approximately trapezoidal.